/*
 * Lua RTOS, ping utility
 *
 * Copyright (C) 2015 - 2017
 * IBEROXARXA SERVICIOS INTEGRALES, S.L. & CSS IBÉRICA, S.L.
 *
 * Author: Jaume Olivé (jolive@iberoxarxa.com / jolive@whitecatboard.org)
 *
 * All rights reserved.
 *
 * Permission to use, copy, modify, and distribute this software
 * and its documentation for any purpose and without fee is hereby
 * granted, provided that the above copyright notice appear in all
 * copies and that both that the copyright notice and this
 * permission notice and warranty disclaimer appear in supporting
 * documentation, and that the name of the author not be used in
 * advertising or publicity pertaining to distribution of the
 * software without specific, written prior permission.
 *
 * The author disclaim all warranties with regard to this
 * software, including all implied warranties of merchantability
 * and fitness.  In no event shall the author be liable for any
 * special, indirect or consequential damages or any damages
 * whatsoever resulting from loss of use, data or profits, whether
 * in an action of contract, negligence or other tortious action,
 * arising out of or in connection with the use or performance of
 * this software.
 *
 * --------------------------------------------------------------------------------
 * Lua RTOS ping utility is based on the following source code:
 *
 * https://github.com/goertzenator/lwip/blob/master/contrib-1.4.0/apps/ping/ping.c
 *
 * --------------------------------------------------------------------------------
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 */

#include <math.h>
#include <float.h>
#include <signal.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>

#include "ping.h"

#include "lwip/inet_chksum.h"
#include "lwip/ip.h"
#include "lwip/ip4.h"
#include "lwip/err.h"
#include "lwip/icmp.h"
#include "lwip/sockets.h"
#include "lwip/sys.h"
#include "lwip/netdb.h"
#include "lwip/dns.h"

#include <sys/delay.h>
#include <sys/driver.h>

#include <drivers/net.h>

static uint16_t ping_seq_num;
static uint8_t stopped = 0;

/*
 * Statistics
 */
static uint32_t transmitted = 0;
static uint32_t received = 0;
static float min_time = 0;
static float max_time = 0;
static float mean_time = 0;
static float last_mean_time = 0;
static float var_time = 0;

#define PING_ID 0xAFAF

#define PING_DEFAULT_COUNT    10
#define PING_DEFAULT_INTERVAL  1
#define PING_DEFAULT_SIZE     32
#define PING_DEFAULT_TIMEOUT   1

/*
 * Helper functions
 *
 */
static void ping_prepare_echo( struct icmp_echo_hdr *iecho, uint16_t len) {
	size_t i;
	size_t data_len = len - sizeof(struct icmp_echo_hdr);

	ICMPH_TYPE_SET(iecho, ICMP_ECHO);
	ICMPH_CODE_SET(iecho, 0);
	iecho->chksum = 0;
	iecho->id     = PING_ID;
	iecho->seqno  = htons(++ping_seq_num);

	/* fill the additional data buffer with some data */
	for(i = 0; i < data_len; i++) {
		((char*)iecho)[sizeof(struct icmp_echo_hdr) + i] = (char)i;
	}

	iecho->chksum = inet_chksum(iecho, len);
}

static err_t ping_send(int s, ip4_addr_t *addr, int size) {
	struct icmp_echo_hdr *iecho;
	struct sockaddr_in to;
	size_t ping_size = sizeof(struct icmp_echo_hdr) + size;
	int err;

	iecho = (struct icmp_echo_hdr *)mem_malloc((mem_size_t)ping_size);
	if (!iecho) {
		return ERR_MEM;
	}

	ping_prepare_echo(iecho, (uint16_t)ping_size);

	to.sin_len = sizeof(to);
	to.sin_family = AF_INET;
	inet_addr_from_ipaddr(&to.sin_addr, addr);

	if ((err = sendto(s, iecho, ping_size, 0, (struct sockaddr*)&to, sizeof(to)))) {
		transmitted++;
	}

	return (err ? ERR_OK : ERR_VAL);
}

static void ping_recv(int s) {
	char buf[64];
	int fromlen, len;
	struct sockaddr_in from;
	struct ip_hdr *iphdr;
	struct icmp_echo_hdr *iecho = NULL;
	char ipa[16];
	struct timeval begin;
	struct timeval end;
	uint64_t micros_begin;
	uint64_t micros_end;
	float elapsed;

	// Register begin time
	gettimeofday(&begin, NULL);

	// Send
	while((len = recvfrom(s, buf, sizeof(buf), 0, (struct sockaddr*)&from, (socklen_t*)&fromlen)) > 0) {
		if (len >= (int)(sizeof(struct ip_hdr)+sizeof(struct icmp_echo_hdr))) {
			// Register end time
			gettimeofday(&end, NULL);

			/// Get from IP address
			ip4_addr_t fromaddr;
			inet_addr_to_ipaddr(&fromaddr, &from.sin_addr);

			strcpy(ipa, inet_ntoa(fromaddr));

			// Get echo
			iphdr = (struct ip_hdr *)buf;
			iecho = (struct icmp_echo_hdr *)(buf + (IPH_HL(iphdr) * 4));

			// Print ....
			if ((iecho->id == PING_ID) && (iecho->seqno == htons(ping_seq_num))) {
				received++;

				// Get elapsed time in milliseconds
				micros_begin  = begin.tv_sec * 1000000;
				micros_begin += begin.tv_usec;

				micros_end  = end.tv_sec * 1000000;
				micros_end += end.tv_usec;

				elapsed = (float)(micros_end - micros_begin) / (float)1000.0;

				// Update statistics
				// Mean and variance are computed in an incremental way
				if (elapsed < min_time) {
					min_time = elapsed;
				}

				if (elapsed > max_time) {
					max_time = elapsed;
				}

				last_mean_time = mean_time;
				mean_time = (((received - 1) * mean_time) + elapsed) / received;

				if (received > 1) {
					var_time = var_time + ((elapsed - last_mean_time) * (elapsed - mean_time));
				}

				// Print ...
				printf("%d bytes from %s: icmp_seq=%d time=%.3f ms\r\n", len, ipa,
					  ntohs(iecho->seqno), elapsed
				);

				return;
			} else {
				// TODO
			}
		}
	}

	if (len < 0) {
		printf("Request timeout for icmp_seq %d\r\n", ping_seq_num);
	}
}

static void stop_action (int i) {
    signal(i, SIG_DFL);

    stopped = 1;
}

/*
 * Operation functions
 *
 */
void ping(const char *name, int count, int interval, int size, int timeout) {
  driver_error_t *error;
  struct sockaddr_in address;
  ip4_addr_t ping_target;
  int s;

  // Get default values if argument are not provided
  if (count == 0) {
	  count = PING_DEFAULT_COUNT;
  }

  if (interval == 0) {
	  interval = PING_DEFAULT_INTERVAL;
  }

  if (size == 0) {
	  size = PING_DEFAULT_SIZE;
  }

  if (timeout == 0) {
	  timeout = PING_DEFAULT_TIMEOUT;
  }

  // Create socket
  if ((s = socket(AF_INET, SOCK_RAW, IP_PROTO_ICMP)) < 0) {
	  // TODO: error
	  return;
  }

  // Resolve name
  if ((error = net_lookup(name, &address))) {
	  // TODO: error
	  return;
  }

  ping_target.addr = address.sin_addr.s_addr;

  // Setup socket
  struct timeval tout;

  // Timeout
  tout.tv_sec = timeout;
  tout.tv_usec = 0;

  if (setsockopt(s, SOL_SOCKET, SO_RCVTIMEO, &tout, sizeof(tout)) < 0) {
	  closesocket(s);
	  // TODO: error
	  return;
  }

  stopped = 0;
  transmitted = 0;
  received = 0;
  min_time = FLT_MAX;
  max_time = 0.0;
  mean_time = 0.0;
  var_time = 0.0;

  // Register signal for stop ping
  signal(SIGINT, stop_action);

  // Begin ping ...
  char ipa[16];

  strcpy(ipa, inet_ntoa(ping_target));
  printf("PING %s (%s): %d data bytes\r\n", name, ipa, size);

  ping_seq_num = 0;

  while ((ping_seq_num < count) && (!stopped)) {
    if (ping_send(s, &ping_target, size) == ERR_OK) {
      ping_recv(s);
    }
    delay(interval * 1000);
  }

  closesocket(s);

  printf("%d packets transmitted, %d packets received, %.1f%% packet loss\r\n",
		  transmitted,
		  received,
		  ((((float)transmitted - (float)received) / (float)transmitted) * 100.0)
  );

  if (received) {
	  printf("round-trip min/avg/max/stddev = %.3f/%.3f/%.3f/%.3f ms\r\n", min_time, mean_time, max_time, sqrt(var_time / received));
  }
}
